Dean's scoring system has been used extensively in assessing fluorosis in the U.S. The traditional method of summarizing the level of fluorosis in a subject is the Dean Index. Statistical methods of comparing the level of fluorosis in different communities using Dean's Index are also being investigated together with other summary measures of fluorosis based on the Dean Scoring System. Data from four communities in Illinois having optimum and higher than optimum levels of fluoride in their water supplies were analyzed using ridit weights assigned to the Dean's Index scores of these subjects. A well established gradient in the level of fluorosis as a function of F concentration was demonstrated.